For nearly two years back in the early 1960s, a man who came to be known as the “Boston Strangler” preyed on women, sexually assaulting and killing 11 of them – many in their homes.

The crimes were never successfully prosecuted, although Albert DeSalvo confessed to being the serial killer several years later. But Mr. DeSalvo later recanted his confession, and in 1973 he was stabbed to death at the state prison in Walpole, Mass., where he was serving a life sentence for armed robberies and sexual assault involving other victims.

Now, Massachusetts law enforcement authorities say they have enough physical evidence to link DeSalvo to the murder of 19-year-old Mary Sullivan – the last of the Boston Strangler’s victims – in her apartment in 1964.

DNA from the scene of Ms. Sullivan's rape and murder has produced a "familial match" with DeSalvo, Suffolk County district attorney Daniel Conley said Thursday. The new physical evidence came from a water bottle discarded by a nephew of DeSalvo.

"There was no forensic evidence to link Albert DeSalvo to Mary Sullivan's murder until today," Mr. Conley said at a news conference. Conley said he expected investigators to find an exact match when the evidence is compared with DeSalvo’s DNA, which will be obtained when his body is exhumed.

Conley acknowledged widespread disagreement among law enforcement and researchers who have investigated the killings whether DeSalvo did in fact kill all the women, The Boston Globe reported Thursday.

“At this point in time, 50 years removed from those deaths and without the biological evidence that we have in the Sullivan case, that is a question that we cannot answer,’’ Conley said. “But these developments give us a glimmer of hope that there can be one day finality, if not accountability, for the families of the 10 other women murdered so cruelly in Boston, Cambridge, Lawrence, Lynn, and Salem.’’

Unsolved for decades, the case continued to fascinate the public even though the string of killings thought to be linked to the Boston Strangler seemed to have stopped. Dozens of books were written. Actor Tony Curtis played DeSalvo and Henry Fonda the lead detective in the 1968 Hollywood version.

Celebrity attorney F. Lee Bailey, who helped to obtain the confession from DeSalvo, said Thursday's announcement will probably help put to rest speculation over the Boston Strangler's identity.

Mr. Bailey had been representing another inmate who informed the attorney that DeSalvo, who was already in prison for the other crimes, knew details of the crimes. Bailey went to police with the information, and he said that DeSalvo demonstrated he knew details only the killer would know.

Bailey would later represent DeSalvo.

"It was a very challenging case," said Bailey, who lives in Yarmouth, Maine. "My thought was if we can get through the legal thicket and get this guy examined by a team of the best specialists in the country, we might learn something about serial killers so we could spot them before others get killed."

If this new evidence proves conclusive, one – and only one – of the Boston Strangler cases will have been solved. No DNA evidence is believed to exist for the other Boston Strangler slayings.